Russia's Foreign Ministry warned on Thursday that it reserves the right to respond harshly to Japanese plans to deploy missiles on an island off Taiwan's coast.

Japan's Defense Minister Shinjiro Koizumi said on Sunday that plans were "steadily moving forward" to deploy a medium-range surface-to-air missile unit at a military base on Yonaguni, an island in the Okinawa Prefecture about 110 km (68 miles) off Taiwan's east coast.

Moscow accused Tokyo of acting on U.S. orders, saying Japan was "pumping these islands with weapons" as part of a broader militarisation effort.